While wall forming systems have been in use for many years, a recent development in this industry is in the use of rigid polystyrene insulation panels as forms for poured concrete walls. After the concrete has hardened, the panels may be left in place on the walls to serve as permanent insulation, or they may be stripped off to reveal the exposed concrete.
Upon introduction of this new wall forming system, it was found that it was unnecessary to use small "building blocks" to create the forming system for the concrete wall. Rather, larger and larger panels are now being utilized to create the concrete forms. As the panels grew in size, the applicant herein devised new types of ties, such as that described in U.S. Pat. No. 4,765,109, which has special ends that could be "knocked off" to easily remove the large panels from the walls. While that patented tie has proven successful for its intended purpose, there are various instances where a different kind of tie would be more convenient and useful.
One problem with the previous tie design was in situations where a large 4'.times.8' panel was desired to be used as the forming structure. Because the previous ties were designed to fit in slots in the upper or lower edges, it was not possible to insert a tie intermediate the edges in the panel. Two solutions to this particular problem are disclosed in the inventor's U.S. Pat. Nos. 4,936,540 and 4,938,449, wherein one or both ends have a tie were provided with beveled ends to permit the tie strap to be forced through the polystyrene panel. A removable end piece was then utilized to engage the tie and retain the form panels in position. While these tie designs also proved useful, they still required that portions of the tie be cut away to permit use of the ties in situations where the form panels were to be removed to expose the concrete wall surface.
Another problem with prior art forming systems was in the use of ties which would retain the insulation panel permanently on the wall. Such systems were not capable of use on those occasions where an exposed concrete surface was desired. In such instances, it was necessary to revert to the older methods of wooden forms which could be removed from the wall, but which left markings on the concrete wall which remained after removal of the forms. While the applicant's tie design of U.S. Pat. No. 4,765,109 solved many of these problems in the use of its "knock off ends", those ties could not be utilized in any location other than the edges of the panels. Similarly, the tie designs of U.S. Pat. Nos. 4,936,540 and 4,938,449 utilized reusable end pieces but still required portions of the ties to be cut away in those locations where concrete was to be exposed.